package acwing._2LanQiao._2BinarySearch_PrefixSum;

import java.util.Scanner;

/**
 * @Project : ProgrammingExercises
 * @Package : ACWing._2LanQiao._2BinarySearch_PrefixSum
 * @File : Q0790.java
 * @Author : WangRuoyu
 * @Date : 2023/3/13 16:12
 */
public class Q0790 {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        double n = scan.nextDouble();

        double l = -10000;
        double r = 10000;

        while (r - l > 1e-8) {
            double mid = (l + r) / 2;
            if (mid * mid * mid == n) {
                System.out.println(mid);
                return;
            } else if (mid * mid * mid > n) {
                r = mid;
            } else {
                l = mid;
            }
        }
        System.out.println(String.format("%.6f", l));
    }
}
